Centrifugal mold



Patented Nov. l0, 1925.

N UNITED STATES P'ATENroFFICE.

JOHNH. U'HIRIG', 0F BEVERLY, NEW'JERSEY, ASSIGNOR TO UNITED STATES GAST IRON PIPE &; FOUNDBY COMPANY, 0F BURLINGTON, NEW JERSEY, A. CORPORATION OF.

p lNew, JERSEY.

cnNrBIr-UGAL Morin.,l l

Application med February 21, 192s. smal no. escaso.

To all 'whom t may concern:

Be it known that I, JOHN H. `UHRIG, a citizen of the United States of America, and resident of Beverly, inv the county of Burlington, in the. State of New Jersey, have invented a certain new and useful Improvement in CentrifugalMolds, of which the following is a true and exact description, reference being had to the accompanying drawings, which form a part thereof.

My invention relates to centrifugal molds such as are used `in the casting of pipe. Such molds are in practice cooled by a lwater jacket and have quite thick Walls' so as to be sufficiently rigid to retain their form under the exigencies of use. In operation, such molds are subjected to temperature conditions which put the inner portions of thev mold under compression while the outer portions of the mold are under tension.

. wrinkling and upsetting ofthe metal on the ,inner surface of the mold and rapid beatings and coolings may vcause these wrinkled molds to crack open and develop fissures. The tendency to develop ssures under the described conditions is particularly marked in case of a pipe mold having an enlarged end such as a ell and at the enlar ed portion of Ithe mold" and it is founi? in practice that the bell ends of the mold have a much shorter useful life than thecylindrical portions of thel mold. The object of my invention is to provide a vmold which will be, toa large extent, free-'from upsetting 'strains which develop fissures, and my invention consists, generallyspeaking, in forming a centrifugal mold of an outer, comparatively thick walljt'ube and an inner thin wall tube, the outside conformatonvof which, at least infthe operations where the mold is' normally subject to the greatest strains, is of such dimensions as to leave a small clearance space between the inner and outer membersA when both are cold while, when the inner memberis .to upsetting strains, while,

casting it will expand into contact with the outer member. By reason of this construction, lthe inner member can and will expand freely when first heated by the molten metal without having its inner `surface subjected contact with the outer member'` it will be These stresses tend to cause acomparatively free from the upsetting stresses which bring about the formation'.

of fissures. As the deformation and forma-A tion' of fissures is most apt to occur in the bell or .enlarged end of the mold it will ordinarily be suiiicient to provide the bell end of the mold with the independently expansible inner member though obviously the innen member in one or more sections canv be made to extend through the entire length of the mold with advantage.

The nature of my invention and various features of construction which I consider advantageous will be best understood as described in connection with the drawings in which- Figure 1 is a longitudinal sectional elevation of the mold embodying my invention, the central portion of the mold being broken away- ,A s

Figure 2 is an'y end view of the construction shown in Fig. 1, viewed from the right hand end, and

Figure4 3 a detail view illustrating a modification. v

A indicatesv the outer member of a. bell end pipe mold having, as shown, a seat portion indicated at A in the rear of its bell 4portion indicated at A2. A3 is the terminal hanged end of the mold memberdand A* the terminal flanged left hand end of the mold member ending, as shown, in a circular ange A5. B is the casing surrounding the mold and formin a water jacket for cooling the mold mem er water-tight joints being indicated' atC, C, etc., the casing having the end formation indicated at Bf, B2 and B3, so as to form joints for the flanges A3 and A". of the member A. D is the` ordinary core ring used to support the core H, the 4core ring having an inner face D which comes directly in contact with the inner mold member `as will be described. As shoyvn. the core ring D is supported in a rin E which fits in a s eat As of the outer mol ing pulley or gear. E4, E, indicate wedge openlngs formed in the wall E2 and endr plate E", the end plate being secured in posif after coming in# tion through bolts G secured tothe fianged 'end of the member A egtendi through Il energetically cooled and at all times will be openings in the end plateiE am? provided member and forms an extension of an endV with nuts G and spring plate G2 4so thatl the end plate is held in position on the outer mold member by yielding elastic means. F, F, are Wedges driven into the Wedgeopenings E* and operating to hold the core ring D in position in the seat member E.

I'is an annular ring secured togthe left hand end of the member A by bolts J, nuts J and springs J 2, the portion I of the annularring -I preferably fitting on Ythe inside of the member A, as indicated, and being prefer-ably somewhat inclinedas shown. K indicates the end of the pouring runner through which the molten metal is introduced into the mold. L indicates an inner mold member which, as shown, is of such dimensions as to extend over the bell end of the mold and somewhat beyond the bell end Where, by preference, I form it with a seat portion L adapted to form a` close fit with the seat portion lA of the mold member A while the enlarged or bell portion of the inv ner' member which is of relatively small Athickness compared with the outer member A lias such utside conformation that it will when both mold members are cooled not come in contact with the enlarged portion A2 of the outer member but leave a space between the inner and outer members which, however, is closed and both members brought into contact with each other throughout their length when the inner member is heated by shown, and by preference, I form the inner member with a terminal flange L4 which fits against a seat A7 of the outer, member, Aas shown, and also lits against the seat por tion D of the core ring.

In the modication shown in Figure 3, the innery mold member L is `shown as only extending slightly beyond the enlarged or bell end of the outer mold member and as abutting against a solid portion of the mold member A. -In the construction of Figure 1, however, I havefillustra'ted a coinbination of the inner mold member, preferably in a separate section throughout the length of the mold, this inner member extension being indicated at L5 and being formed withconical ends L6 and L'rn which fits against conical end surfaces L2 and I', this construction tending to center the portion Ll5 of the inner member when both mold members are cold and the inner member L, therefore, out of contact with the inner surface of the outer 'mold member. Y YIt will be observed that I have provided for the independent longitudinal extension of the inner mold member by making the abutting portions of the mechanism elasti-A cally yielding; in the one case the springs G2 permitting thecore'ring seat E and other parts to move outward Vunder a longitudinal thrust and, in the other-case,.the springs J2 permitting the' angular ring I tozmove section L, is comparatively short, there will ordinarily be suiiicient elastic yielding in the Wedges'F to permit of the necessary longitudinal extension of the mold member when requiring the use of the springs G. A y

Having now describedl my invention, what I claim as new and desire to secure by Letters Patent, is: -y

1. A centrifugal mold comprising an outer metallic tubular member with comparatively thick walls and an inner thin walled metal lic tubular member the external diameter of which is less than the inner diameter of the outer member when both members are cold and so proportioned that the inner member will contact with the outer member when said inner member is expended by the heat of a charge of molten metal. X,

2. Acentrifugal mold comprising an outer metallic tubular member with comparatively thick walls and an inner thin walled metallic tubular .nem-ber the externalI diameter of which is less than the inner diameter of the outer member when both members are cold and so proportioned that the inner member will contact with the outer member when said inner member is expanded by the heat of a char e of molten metalin combination with 'an e astically yielding abutment for the inthemolten metal 'poured into the mold. As

ner member.

3. A centrifugal mold com rising an outer metallic tubular member wi com aratively thick walls and an inner thin wal ed metallic` tubular member the external diameter of which is less than the inner diameter of the outer member when-both members are cold and so proportioned that the inner member willcontact with the outer member when said inner member is expanded bythe heat of a charge of molten metal, in combination with means for water cooling the outer member.

4. A centrifugal mold comprising an outer metallic tubular member with comparatively thick walls and an inner thin walled metallic tubular member the external diameter of which is less than the inner diameter of the outer member when both members are cold and so proportioned that the inner member will contact with the outer member when said inner `member is expanded by the heat of a charge of molten metal, in combination with means for water coolin the outer member and anl elastically yiel ing abutm nt for the inner member.

5. A centrifugal pipe mold for pipes havingl enlar ed ends comprising an outer metallic tuular member with comparatively thick walls and an enlarged end, and an inner thin walled metallic tubular member having also an enlarged end ythe outer conformation of which is such as to leave a clearance between it andthe enlarged end of the outer member when bothV members are cold and to contact with such outer members when the inner member 'is heated.

and expanded bya charge of molten metal.

6. A centrifuga-l pipe mold for pipes having enlarged ends comprising an outer metallic tubular member with comparatively thick Walls and an enlarged end, and an inner thin walled metallic tub'ularmember having also an enlarged end the outer conformation of which is such as to leave a e clearance between it and the enlar ed end of the outer member When both mem ers are cold and to contact with such outer member when the inner member is heated andexpanded by a charge of molten metal, said inner member having a seatpcrtion of such diameter as to form a close fit when cold with a seat in the outer member located in the rear of its enlarged end.

7. A centrifugal mold comprising an outer metallic tubular member with comparatively thick wallsan inner thin walled metallic tubular member litting loosely in the outer member and yielding `elastic abutment for the inner member whereby said .inner member is 'ven freedom to expand longitudinally'- inipendently of the outer member.

JOHN H. UHRIG. 

